Back Door Gun Control? California to Allow Family Members to Seek Seizer of Guns

California will be the first state in the country to allow private citizens to ask a court to seize guns from family members who they believe pose a threat to themselves or the public, under a measure signed into law by Gov. Jerry Brown on Tuesday.

The law will allow law enforcement officials, family members and some others to seek a gun restraining order from a judge. That order would authorize officials to temporarily seize any firearm owned by someone deemed potentially violent, who would also be placed on a list of people prohibited from purchasing weapons.

“This puts California in the leadership on efforts to stop gun violence, and it gives a very effective tool to law enforcement and families to intervene before a shooting tragedy occurs,” said Nancy Skinner, the California assemblywoman who sponsored the bill.

Several states have passed laws allowing law enforcement officials to petition to take firearms from people considered dangerous, but California is the first to allow family members to do so as well — a provision that gun control advocates said would be crucial in preventing suicides as well as mass shootings.

“Family members are the ones who most acutely understand when their loved ones are in a dangerous situation,” said Josh Horwitz, the executive director of the Coalition to Stop Gun Violence, which lobbies for stricter gun control across the country. “Now, when they see dangerous behavior — whether because of substance abuse or a mental health issue or a traumatic brain injury — a court can act.”

The legislation was introduced in direct response to the shooting in Isla Vista, Calif., in May, when Elliot O. Rodger, 22, killed six people and wounded more than a dozen others. Mr. Rodger had legally purchased three firearms in the preceding months and had been able to keep them even though his family warned the police that he might be unstable.